I am presently reading Nation by the inimitable Mr Pratchett. It's been sitting around for a while, waiting for me to really get stuck into it. I am about a third of the way through, it's going well, and here is my opinion thus far.
If you learn nothing else as an English graduate, it's that a) there is a distinct canon of great British authors respected by the majority of academic figures and "serious" critics, and b) they are awfully snobby about adding names to it. Genre fiction, in particular, is largely a no-no, and anyone who gets stocked in the "Fantasy and Science Fiction" section of your local Waterstone's is usually pooh-poohed. (Standard grandfather clauses apply; Tolkien usually gets a pass)
Terry Pratchett is beloved of a certain breed of open-minded reviewer as being a modern-day humourist who can compete with the best of the classics, but he still had that stigma to overcome. But in fifty, a hundred years' time, when his career is largely passed from memory, I believe his name will now be up there on the shelf, and the brass plaque beneath his portrait will read Nation.
Not just because it's not a Discworld book, although I think that may help a little. This isn't the sort of situation where Return of the King won all those Oscars it didn't really deserve because the trilogy as a whole did, although I would say that being a standalone book does help Nation to stand on its own two feet. No, I would say that it is because, even based on my limited reading of it so far, Nation is not just a good book, not just probably the best thing Pratchett has written, but a legitimate masterpiece of writing in the English language.
I am usually cautious of opinions at first blush. I may change my mind later and come back and laugh at my naiveté. Somehow, however, I'm willing to give Terry the benefit of the doubt on this one.